1. Field of the Invention
The invention is in the field of communications and more specifically in the field of internet communication protocols.
2. Related Art
Internet communications depend on a Domain Name Service (DNS) through which domain names, such as www.nominum.com, are converted to numerical internet protocol (IP) addresses for use by switches, routers and other physical devices included in the internet. Typically, when a first device wishes to communicate with a second device represented by a domain name (or similar label), the first device sends out a DNS request to a local DNS server. The DNS request includes the domain name of the second device and a return IP address of the first device/requestor. The local DNS server may forward the request to an authoritative server that has an (IP) address corresponding to the requested domain name. In the prior art, each domain name request should return the IP addresses corresponding to the domain name. These IP addresses are found through the identification of an exact match or wildcard match for the domain name on a DNS server. A DNS server may be used for identifying other types of data including MX (Mail Exchange) records, PTR (Pointer) records for IP-to-name translation, NAPTR (Naming Authority Pointer) records for ENUM (Telephone Number Mapping), and the like.
The DNS namespace is hierarchical. For example, the domain name “nominum.e164.arpa.” includes the root domain, “.”, the global top level domain “arpa,” a sub-domain “e164,” and a sub-sub-domain “nominum.” nominum.e164.arpa constitutes an example of a DNS zone. Each zone is operated under a DNS authority within the hierarchical structure of DNS. DNS zones are the unit under which DNS data is replicated to authoritative DNS servers. For example, in a “zone transfer” a DNS zone may be copied from a first authoritative server managed by an owner of the DNS zone to a second server. This second server may be managed by the zone owner, or may be managed by another party. Receipt of a mirror copy of the DNS zone by the second server establishes the second server as a second authoritative server. DNS protocols include a variety of procedures for maintaining the concurrency of these two copies of the DNS zone. Typically, a DNS zone is controlled and owned by a single entity, e.g., nominum.
Generally, a DNS zone includes a portion of the global DNS namespace under which responsibility has been delegated and not re-delegated. For example, the root domain “.” is associated with a DNS zone that includes all of the global DNS namespace except for those parts of the global DNS namespace that have been re-delegated to a top level domain such as “.com”. The domain “.com” domain is associated with a DNS zone that includes all of the DNS namespace delegated to “.com” except for those parts of the “.com” namespace that have been delegated to a sub-domain such as “nominum.com”. The “nominum.com” domain in associated with the DNS zone delegated from “.com”, except for any that may be further delegated by the authority that controls “nominum.com”.
Internet protocols are now being used for a wide range of different applications. For example, telephone calls may now be connected and routed using the DNS system. These and other applications are placing increasing demands on the DNS system. There is, therefore, a need for expanding the capabilities of DNS while maintaining compatibility with current uses.